Cellulosic fiber composites using protein hydrolysates and methods of making same

ABSTRACT

Cellulosic fiber composites and methods for preparing cellulosic fiber composites are provided. The cellulosic fiber composites comprise cellulosic material and a resin binder. The resin binder comprises protein hydrolysates and a synthetic resin. The synthetic resin can be phenolic resin, isocyanate resin, or combinations thereof. The protein hydrolysates provide a composite with a reduced amount of petrochemicals. The composite contains an amount of resin binder sufficient to bind the cellulosic material. The composite can also contain a silicone, silane, or combination thereof. The method employs a low moisture-content mat that does not require drying prior to pressing. Additional methods can be employed to produce finished cellulosic fiber composite articles.

BACKGROUND OF THE INVENTION

The present invention relates generally to cellulosic fiber compositesusing protein hydrolysates, and to the method of using proteinhydrolysates in the manufacture of agricultural and other cellulosicfiber composites.

Currently, petroleum based binders such as polymeric isocyanates,phenolic and other formaldehyde-based resins, including phenolformaldehyde, phenol resorcinol formaldehyde, and urea formaldehyde, areemployed in the manufacture of cellulosic fiber composites such asagfiber board and oriented strand board. However, these binders exhibitseveral disadvantages such as formaldehyde emissions, high temperaturerequirements to enable the binders to set, difficulty in handling ofresins, and high materials and production costs. It would be desirableto reduce the amount of phenolic and isocyanate resin employed in theproduction of cellulosic fiber composites.

U.S. Pat. No. 4,944,823 ('823) describes a method for bonding woodsurfaces together by heating and pressing using a dry binder formulationconstituting a thorough mixture of an isocyanate and a carbohydrate suchas a sugar or starch in the manufacture of composite wood products. Thesugar or starch replaces a quantity of the isocyanate which wouldnormally have been used, thereby reducing the total quantity ofisocyanate. However, the binder described by the '823 patent does notinclude a source of protein nor protein hydrolysate.

Natural legume-based resins have been employed with cellulosic materialin the preparation of rigid, pressure-formed biocomposites (U.S. Pat.Nos. 5,593,625 and 5,635,123). These embodiments employ close to equalamounts of legume-based resin and fiberous cellulosic solids (40-56%resin solids) in the production of fiber-reinforced, protein-baseddiscrete high moisture-content particles having a moisture content ofabout 55-75% by weight. By assuring that the moisture content remainsabove 59% by weight, the relatively high amount of legume-based resinfully impregnates the particles such that a new composite material isprepared rather than a material that is produced by gluing fiberouscellulosic solids together by an adhesive. The particles can be combinedwith a secondary thermosetting binder to form the biocompositematerials. As a result, preparation of such biocomposites requires anadditional drying step to reduce the moisture content to less than about20% by weight prior to pressing.

It would be desirable to produce finished cellulosic fiber compositesthrough a method which employs materials having a relatively lowmoisture content and which does not require an additional drying stageor step. Therefore, there remains a need for a new fiber-adhesive, resinbinder system for use in the manufacture of agricultural and othercellulosic fiber composites, which reduces the amount of phenolic and/orisocyanate resin needed.

SUMMARY OF THE INVENTION

The present invention meets this need by providing cellulosic fibercomposites, methods for preparing cellulosic fiber composites, andfinished cellulosic fiber composite articles. The cellulosic fibercomposites comprise a cellulosic material and a resin binder comprisingprotein hydrolysates and a synthetic resin, wherein the synthetic resinis phenolic resin, isocyanate resin, or combinations thereof. Thecomposites contain an effective amount of resin binder so as to bindtogether the cellulosic material.

In accordance with the present invention, a resin binder is prepared byfirst hydrolyzing protein to produce protein hydrolysates. The proteincan be animal protein, vegetable protein, or combinations thereof. Moreparticularly, the vegetable protein can be soy isolate, soy flour, or ablend thereof.

The resultant protein hydrolysates can be mixed with a synthetic resinto produce a resin binder. The synthetic resin of the resin binder canbe phenolic resin, isocyanate resin, or combinations thereof. The amountof resin binder included in the composite can be between about 2% andabout 15% of the dry weight of the cellulosic material. Optionally, theamount of resin binder included in the composite can be between about 4%and about 8%, between about 4% and about 6%, or between about 4% andabout 5% of the dry weight of the cellulosic material.

After application of the resin binder, the average moisture content ofthe cellulosic material can be between about 8% and about 35% by weight.If the synthetic resin is phenolic resin, the weight ratio of proteinhydrolysates to phenolic resin making up the resin binder can be betweenabout 10:90 and about 90:10. Optionally, this weight ratio can bebetween about 10:90 and about 75:25. Alternatively, this weight ratiocan be between about 25:75 and about 75:25, or between about 25:75 andabout 50:50.

If the synthetic resin is isocyanate resin, the weight ratio of proteinhydrolysates to isocyanate resin making up the resin binder can bebetween about 10:90 and about 90:10. Optionally, this weight ratio canbe between about 10:90 and about 75:25. Alternatively, this weight ratiocan be between about 25:75 and about 75:25, or between about 25:75 andabout 50:50.

Optionally, the synthetic resin may also be a combination of phenolicresin and isocyanate resin. The weight ratio of the isocyanate resin tothe total of the protein hydrolysates and the phenolic resin making upthe resin binder can be between about 25:75 and about 75:25.

Optionally, the synthetic resin can further comprise paraformaldehyde.The weight ratio of the paraformaldehyde to the total of the proteinhydrolysates and the synthetic resin making up the resin binder can bebetween about 2:48 and about 15:35 based on 50% resin solids.

Optionally, the synthetic resin can further comprise a high methylolcontent phenol formaldehyde pre-polymer. The weight ratio of the highmethylol content phenol formaldehyde pre-polymer to the total of theprotein hydrolysates and the synthetic resin making up the resin bindercan be between about 10:90 and about 90:10. Optionally, this weightratio can be between about 25:75 and about 75:25.

Optionally, the cellulosic fiber composite can further comprise asilicone, silane, and combination thereof. The silicone, silane, orcombination thereof can be applied as a coating to the composite, or itcan be added to the resin binder to improve such properties as hightemperature strength, water resistance, and decreased swelling caused byabsorption of water.

The present invention is also directed to methods for preparingcellulosic fiber composites. These methods comprise: mixing a proteinhydrolysate with a synthetic resin to produce a resin binder. Thesynthetic resin can be phenolic resin, isocyanate resin, or combinationsthereof. The protein hydrolysates are prepared by hydrolyzing a sourceof protein with sodium carbonate. The synthetic resin can furthercomprise paraformaldehyde or high methylol content phenol formaldehydepre-polymer. These methods further comprise: mixing the resin binderwith cellulosic material, wherein the amount of resin binder added canbe between about 2% and about 15% of the dry weight of the cellulosicmaterial, to form a cellulosic material/resin binder blend; felting thecellulosic material/resin binder blend to form a low moisture-contentmat; and pressing the low moisture-content mat at an elevatedtemperature and pressure, producing a cellulosic fiber composite. Themoisture content of the composite can later be adjusted to apredetermined amount. A silicone, silane, or combination thereof mayalternatively be applied to the cellulosic fiber composite as a coating,or added as part of the resin binder.

In addition, the present invention is also directed to finishedcellulosic fiber composite articles, as well as methods for preparingfinished cellulosic fiber composite articles. Alternatively, a laminateoverlay can be applied to these finished articles.

Accordingly, it is an object of the present invention to providecellulosic fiber composites comprising cellulosic material and a resinbinder in which the resin binder contains a reduced amount ofpetrochemicals, and to provide methods for preparing such composites.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the present invention can be bestunderstood when read in conjunction with the following drawings:

FIG. 1 is a plot diagram showing soy hydrolysate viscosity versus shearrate for each resin binder. The legend refers to the flour loading inmass percent.

FIG. 2 is a response curve diagram showing peak molecular weight ofhydrolysate versus time and temperature of hydrolysis.

FIG. 3 is a response curve diagram showing total amine level ofhydrolysate versus time and temperature of hydrolysis.

FIG. 4 is a diagram showing the relationship between internal bondstrength (IB) and resin content, blend ratio, hot press time andtemperature.

DETAILED DESCRIPTION

The cellulosic fiber composite of the present invention comprisescellulosic material and a resin binder that comprises proteinhydrolysates and a synthetic resin, wherein the synthetic resin isphenolic resin, isocyanate resin, or combinations thereof. The compositecontains an effective amount of resin binder so as to bind together thecellulosic material. By effective amount we mean the addition of resinbinder in an amount so that it acts as an adhesive for the cellulosicmaterial and not in an amount so that it is a major constituent of thecomposite. By effective amount we do not mean an amount sufficient tofully impregnate the cellulosic material, nor do we mean an amountsufficient to coat and encapsulate the cellulosic material.

This composite can be used in the production of agricultural and othercellulosic fiber composites such as agfiber board and oriented strandboard that exhibit properties not obtained by the earlier products. Byreplacing a percentage of the synthetic resin with protein hydrolysatesin a binder system for the manufacture of cellulosic fiber composites,the present invention overcomes many of the disadvantages of previouspetroleum-derived resin binder systems. By using less synthetic resin(including formaldehyde-based resin), the cellulosic fiber composite ofthe present invention reduces formaldehyde emissions commonly associatedwith this type of composite. Also, because phenolic and isocyanateresins are difficult to handle in processing, the present inventionfurther diminishes this drawback of previous synthetic resin bindersystems.

The cellulosic material can be any suitable fiberous substance orsubstances that can be combined with a resin binder to produce acellulosic fiber composite. For example, typical cellulosic fibers foruse in the present invention include, but are not limited to, mixedhardwood or any other type of wood flake, as well as agricultural fibersuch as wheat straw, rice straw, or combinations thereof. However, nospecific source of cellulosic material is required.

The protein hydrolysate of the present invention can be any animal orvegetable protein source, or combination thereof. A typical source ofvegetable protein is a legume-based protein such as soy protein. The soyprotein can be soy isolate, soy flour, or a blend thereof. The weightratio of this soy protein blend of soy isolate to soy flour can be about50:50. By replacing a percentage of the synthetic resin with relativelyinexpensive soy flour, the resultant synthetic resin binder system ofthe present invention provides an economically and environmentallyfavorable alternative to pure phenolic and isocyanate resin bindersystems.

Soy protein is a complex biopolymer with a three dimensional structurewith various fractions such as 2S, 7S and 11S protein components.Glycenin and conglycenin are the major components of protein isolate.Soy protein in its native state is only sparingly soluble. Acids andbases in the presence of heat can readily break down the structure andincrease its water solubility. Further, such hydrolyzed fractions,mainly polypeptides, have exposed functional amino groups derived fromlysine and N-terminal amino acids useful in cross-linking reactions withsynthetic resins.

Hydrolysis of the protein source is employed to take advantage ofreactive groups available in the protein to produce both strong andrapid cross-linking reactions with synthetic resin. Hydrolysis can beperformed by alkaline hydrolysis. Although the inventors do not wish tobe held to any particular theory, it is believed that throughhydrolysis, the complex structure of the protein, more particularly, soyprotein, is broken down to lower molecular weight fragments, therebymaking more of its functional groups, such as amine and carboxyl, morereadily available for reaction with synthetic resins and increasing itssolubility in water. When soy flour is employed as the source ofprotein, soy hydrolysate viscosity will increase. Protein hydrolysatescan be produced with the use of up to about 50% soy flour while stillmaintaining viscosity levels effective for typical binder formulation.However, while the testing focused on soy protein, it is contemplatedthat protein of any vegetable or animal source is applicable.

By varying the hydrolysis conditions in which the protein hydrolysatesof the present invention are produced, some of the fundamentalparameters of soy protein hydrolysate, such as molecular weight and itsdistribution, amine functionality, and rheology, can be affected.Alkaline hydrolysis of soy protein derived from soy isolate and soyflour show excellent correlation with time and temperature of hydrolysisto peak molecular weight, solution viscosity, and amine level ofhydrolysates. Temperature of hydrolysis seems to have a more pronouncedeffect than time on these properties. Peak molecular weight and solutionviscosity of hydrolysates decrease with increases in time andtemperature of hydrolysis, due to break down of protein structure. Totalamine level is found to increase with time and temperature of hydrolysisresulting from the generation of N-terminal amino acids, as a result ofthe opening up of the folded protein structure.

The protein hydrolysates of the present invention can be blended with asynthetic resin to produce a resin binder. The synthetic resin can bephenolic resin, isocyanate resin, or combinations thereof. The amount ofthe resin binder included in the composite can be between about 2% andabout 15% of the dry weight of the cellulosic material. The addition ofresin binder should be in an amount so that it acts as a binder oradhesive, and not in an amount sufficient to coat and encapsulate thecellulosic material. Optionally, the amount of resin binder included inthe composite can be between about 4% and about 8% of the dry weight ofthe cellulosic material. More particularly, the amount of resin binderincluded in the composite can be between about 4% and about 6%, orbetween about 4% and about 5% of the dry weight of the cellulosicmaterial.

The amount of resin binder included in the composite should not besufficient to be considered a major constituent of the composite(greater than 40% of the composite). Nor should the amount of resinbinder included in the composite be sufficient so that it fullyimpregnates the cellulosic material. After application of the resinbinder, the average moisture content of the cellulosic material can bebetween about 8% and about 35% by weight. Increases in the viscosity ofthe resin binder are shown as reactive groups available in the proteinsource enhance cross-linking reactions between protein hydrolysates andphenolic resin.

The synthetic resin of the present invention can be phenolic resin. Thephenolic resin can be, but is not limited to, phenol formaldehyde. Atypical weight ratio of protein hydrolysates to phenolic resin making upthe resin binder can be between about 10:90 and about 90:10. Weightratios of protein hydrolysates to phenolic resin are more typicallybetween about 10:90 and about 75:25, between about 25:75 and about75:25, and between about 25:75 and about 50:50.

The synthetic resin of the present invention can optionally be anisocyanate resin. The isocyanate resin can be, but is not limited to,polymeric isocyanate. A typical weight ratio of protein hydrolysates toisocyanate resin making up this resin binder can be between about 10:90and about 90:10. Weight ratios of protein hydrolysates to isocyanateresin are more typically between about 10:90 and about 75:25, betweenabout 25:75 and about 75:25, and between about 25:75 and about 50:50.

The synthetic resin making up the resin binder of the present inventioncan also be a combination of phenolic resin and isocyanate resin. Atypical weight ratio of the isocyanate resin to the total of the proteinhydrolysates and the phenolic resin making up this resin binder can bebetween about 25:75 and about 75:25.

The amount of isocyanate resin making up the cellulosic fiber compositecan be about 1% to about 6% based on the total weight of the cellulosicmaterial. The amount of isocyanate resin making up the cellulosic fibercomposite is more typically about 1% to about 3% based on the totalweight of the cellulosic material. While improvements in strengthproperties and dimensional stability are seen with all the compositescontaining polymeric isocyanate, a cellulosic fiber composite made witha resin binder wherein the amount of isocyanate resin is about 1% toabout 2% based on the total weight of the cellulosic material results instrength properties and dimensional stability equal to or better thantraditional synthetic resin systems and approaches the performance ofpure phenolic and isocyanate resin binder systems.

Alternatively, the synthetic resin of the present invention can furthercomprise paraformaldehyde. A typical weight ratio of theparaformaldehyde to the total of the protein hydrolysates and thesynthetic resin making up this resin binder can be between about 2:48and about 15:35 based on 50% resin solids, or typically about 5% of thecellulosic fiber composite based on 50% resin solids. The addition ofparaformaldehyde can increase viscosity significantly in a relativelyshort period of time. Also, resin cure is accelerated by the addition ofparaformaldehyde.

Optionally, the synthetic resin of the present invention can furthercomprise a high methylol content phenol formaldehyde pre-polymer. Themolar ratio of formaldehyde to phenol to NaOH of the high methylolcontent phenol formaldehyde pre-polymer can be about 2:1:0.5. A typicalweight ratio of the high methylol content phenol formaldehydepre-polymer to the total of the protein hydrolysates and the syntheticresin making up this resin binder can be between about 10:90 and about90:10. The weight ratio of the high methylol content phenol formaldehydepre-polymer to the total of the protein hydrolysates and the syntheticresin making up this resin binder is more typically between about 25:75and about 75:25.

Optionally, the cellulosic fiber composite can further comprise asilicone, silane, or combination thereof. The silicone, silane, orcombination thereof can be applied as a coating to the composite.Alternatively, the silicone, silane, or combination thereof can be addedas part of the resin binder. Silicone and/or silane compounds can beadded to improve several properties of the cellulosic fiber composites.Such properties include high temperature strength, water resistance, anddecreased swelling caused by absorption of water, better enabling thecomposite for exterior applications in which it would be exposed to theelements.

The amount of silicone, silane, or combination thereof comprising thecellulosic composite can be between about 0.1% and about 1.0% of thetotal amount of cellulosic material. While not wishing to be bound byany particular theory, it is contemplated that such silanes may producemoisture-resistant cross-linking reactive bonds to substrates such asthe synthetic resins, protein hydrolysates, and cellulosic material ofthe present invention. Typical silanes include, but are not limited to,those functionalized with amino, epoxy, or urethane groups. Suitablesilanes are available from Witco Corporation, Greenwich, Conn. Thesesilanes can include primary and secondary aminofunctional silanes,di-aminofunctional silanes, epoxy functional silanes and silanecross-linkers.

A method for preparing a cellulosic fiber composite is also provided.The method comprises preparing protein hydrolysates from a source ofprotein by hydrolyzing the protein with sodium carbonate. The resultantprotein hydrolysates are then mixed with a synthetic resin to produce aresin binder. In accordance with the different compositions of resinbinders of the present invention, the protein can be any animal orvegetable protein, including, but not limited to, soy protein from soyisolate, soy flour, or a blend thereof. The synthetic resin can be aphenolic resin such as phenol formaldehyde, an isocyanate resin such aspolymeric isocyante, paraformaldehyde, or high methylol content phenolformaldehyde pre-polymer, in different combinations thereof.

The method further comprises mixing the resin binder with a cellulosicmaterial of the present invention. The amount of resin binder added tothe cellulosic material can be between about 2% and about 15% of the dryweight of the cellulosic material. In accordance with the cellulosicfiber composites of the present invention, the amount of resin binderadded can also be between about 4% and about 8%, between about 4% andabout 6%, or between about 4% and about 5% of the dry weight of thecellulosic material. After adding the resin binder to the cellulosicmaterial, these components are blended together in a blending device toform a cellulosic material/resin binder blend.

The average moisture content of the cellulosic material is between about8% and about 35% by weight after application of the resin binder.Because of the relatively low moisture content of this cellulosicmaterial, no additional drying step or stage is required prior topressing. The method may proceed directly to the next step of feltingthe cellulosic material/resin binder blend to form a lowmoisture-content mat. By low moisture-content mat we mean a mat with amoisture content that is less than about 55% by weight. The cellulosicmaterial/resin binder blend may then be transferred to a hot press. Thehot press then presses the low moisture-content mat comprising thecellulosic material/resin binder blend at elevated temperature andpressure, producing a cellulosic fiber composite. The moisture contentof the composite can then be adjusted to a predetermined amount. Asilicone, silane, or combination thereof may alternatively be applied asa coating, or added as part of the resin binder, improving hightemperature strength and water resistance of the cellulosic composite.

A method for preparing finished cellulosic fiber composite articles isalso provided. This method produces finished cellulosic fiber compositearticles directly from raw cellulosic material. The method saves bothtime and labor as the method eliminates the need to cut and/or sand thecomposite to form the finished article. By eliminating cutting and/orsanding, no material is wasted.

The method comprises mixing the protein hydrolysate of the presentinvention with a synthetic resin to produce a resin binder. Thesynthetic resin can be a phenolic resin such as phenol formaldehyde, anisocyanate resin such as polymeric isocyanate, paraformaldehyde, or highmethylol content phenol formaldehyde pre-polymer, in differentcombinations thereof. The method further comprises mixing the resinbinder with a cellulosic material of the present invention, to form acellulosic material/resin binder blend. The amount of resin binder addedto the cellulosic material, as well as the average moisture content ofthe cellulosic material after application of the resin binder, can be inaccordance with the cellulosic fiber composite of the present invention.Because of the relatively low moisture content of this cellulosicmaterial, no additional drying step or stage is required prior topressing.

The method may proceed directly to the next step of felting thecellulosic material/resin binder blend to form a low moisture-contentmat. By low moisture-content mat we mean a mat with a moisture contentthat is less than about 55% by weight. The cellulosic material/resinbinder blend may then be transferred to a molding press. A suitablemolding press for manufacturing finished cellulosic fiber compositearticles is available Sorbilite Compression Molding Systems, VirginiaBeach, Va. By varying the shape of the mold, it is possible to form avariety of contoured articles such as molded trims, door panels, countertops, and the like. The molding press then molds the lowmoisture-content mat at elevated temperature and pressure, providing thefinished cellulosic fiber composite article.

The method may also produce finished cellulosic fiber composite articleswith decorative laminate overlays by laminating the overlays thereon.

In order that the invention may be more readily understood, reference ismade to the following examples, which are intended to illustrate theinvention, but not limit the scope thereof.

EXAMPLE 1 Hydrolysis

Materials.

Soy isolate (PRO-COTE 200 from Protein Technologies, Inc.) and soy flour(Soy Fluff from Cargill) were evaluated. Samples were made using 100%soy isolate, 100% soy flour, and 50:50 soy isolate: soy flour blend.

Hydrolysis Conditions.

Only alkaline hydrolysis was studied, although we expect other types ofhydrolysis to produce similar resluts. A typical hydrolysis experimentconsisted of making up a sodium carbonate solution in water (about 5.46grams in 104.8 grams of water) and adding 65 grams of protein (eithersoy isolate, soy flour, or a blend thereof) in a stainless steel tubularpressure reactor. To prepare the various hydrolysates, the reactor washeated in an oven with mixing of its contents. Soy protein samples werethen hydrolyzed at various prescribed temperatures and times as shown inTable 1 below. A standard protein content of about 36% solids was used.Hydrolysates were characterized for both molecular weight and aminelevel. Typical values for these parameters are also shown in Table 1below.

TABLE 1 Typical Properties of Hydrolysates from Soy Isolate and FlourPeak Lab Book Time of Temperature Molecular Amine Number ProteinHydrolysis, of Hydrolysis, Weight, Level, Resin I.D. Source Hours Deg CDalton mg/mL 48177-8-01 100% 14 100 20500 60 Pro-Cote 200 48177-8-02100% Soy 24 100 11600 42 Flour 48177-8-03 50:50 24 120 8120 106 Isolate& Flour 48177-8-04 100% — — 20,000 84 (HT-1) Isolate from HoptonIndustries

Molecular Weight of Hydrolysates.

Superose 12 chromatography was done on a 650 E Protein PurificationSystem (Waters) with a Superose 12 HR 10/30 column (Pharmacia,Piscataway, N.J.). The column was run at room temperature with a flowrate of 0.5 ml/min. in phosphate buffered saline, pH 7, that contained0.1% azide. The buffer was filtered through a 0.22-micron filter andstored at 4° C. until use. Fresh buffer was warmed and degassed bysonication prior to each run.

Samples of hydrolyzed soy products were prepared for chromatography bythe addition of 12 μL of soy hydrolysate to 1188 μL phosphate bufferedsaline. The samples were sonicated to get a more uniform solution andvortexed to dissolve the solids. After centrifugation at 15,000 gravityfor 10 minutes at 4° C., the dissolved samples were filtered through a0.22-micron filter prior to injection onto the Superose 12 column.Chromatographic data was collected using Turbochrom software (PerkinElmer).

Various standard proteins, ranging in size from 6,500 to 2,000,000Daltons were prepared in the same buffer and injected into the Superosecolumn to generate a standard curve of size and elution times. Elutiontimes obtained with various hydrolyzed protein samples were used toestimate the molecular weights of hydrolysates.

Total Amine Analysis.

A 1:800 dilution of the hydrolyzed soy sample was prepared in 0.1 Msodium bicarbonate, pH 8.5, and centrifuged. The supernatant was assayedfor amine content. A standard curve using N-acetyl lysine, 4-1000 μg/ml,was prepared in the same buffer.

2,4,6-Trinitrobenzenesulfonic acid was used as a 5% weight/volumemethanol solution and stored at −20° C. Before each assay, thehydrolyzed soy sample was dissolved in 0.1 M sodium carbonate, pH 8.5,at a concentration of 0.012% weight/volume. Using a 96 well microliterplate, a 100 μl sample or standard was added to each well, followed bythe addition of 125 μl of 15% sodium dodecyl sulfate and 25 μl of 1.5 NHCl. The plate was read at 355 nm using a microtiter plate reader.

The protein amino groups that react with 2,4,6-Trinitrobenzenesulfonicacid and thus contribute to the total amine concentration are the lysineside chains and alpha amino groups of each N-terminal amino acid. Therewas poor agreement, however, between the concentration of total aminesdetermined by 2,4,6-Trinitrobenzenesulfonic acid reaction and the numberof amines predicted from lysine concentration and the estimatedconcentration of N-terminal amines. The total amine concentrationestimated in this study must, therefore, be viewed as a relative numbercompared to unhydrolysed samples. Since lysine concentration does notincrease during hydrolysis, any increase in the total amineconcentration must be due to the formation of additional N-terminalgroups by peptide hydrolysis.

Rheology Measurements.

Viscosities of samples were measured on a Rheometric Scientific SR5controlled stress rheometer using a steady stress sweep experiment.Experiments were performed using 25 mm parallel plates at roomtemperature. The samples are identified in the table below. The stresswas varied to obtain viscosity data over several decades of shear rate.

Sample Number Flour % Water % Na₂CO₃ % 48177-8-25 25 69 6 48177-8-29 3064 6 48177-8-17 31 63 6 48177-4-18 36 58 5 48018-35-2 40 55 5 48018-35-150 46 4

A plot of viscosity versus shear rate for each formulation is shown asFIG. 1. The viscosity versus shear rate behavior of all samples wassimilar. All of the samples exhibited significant shear thinning(viscosity reduction with increasing shear rate). The viscosityincreases as the flour level increases. The viscosity of 50% flour istoo high for use in a typical formulation for oriented strand boardproduction. The viscosity versus shear rate plot is linear when plottedon a log—log scale, which is indicative of power law behavior. The powerlaw equation and parameters from the different samples are listed below.In this equation, η is the viscosity (poise), γ is the shear rate, and nis the power law exponent.

η=K{dot over (γ)} ^(n−1)

Sample Number Flour % K n − 1 48177-8-25 25 22.2 −0.59 48177-8-29 30 144−0.72 48177-8-17 31 180 −0.71 48177-4-18 36 619 −0.70 48018-35-2 40 568−0.65 48018-35-1 50 6550 −0.73

EXAMPLE 2 Hydrolysis

Results and Discussion.

In this example, alkaline hydrolysis of soy protein from isolates andflour under varying time and temperature conditions were examined.Hydrolysates were characterized for water solubility, molecular weightand its distribution, amine functionality, and viscosity as described inExample 1 above. Various hydrolysate samples evaluated in the studyalong with hydrolysis conditions and some of their properties are shownin Table 2 below.

TABLE 2 Typical Properties of Hydrolysates from Soy Isolate and FlourTemperature Peak Part A Time of of Molecular Amine Identification InAdhesive Protein Hydrolysis, Hydrolysis, Weight, Level, of AdhesiveFormulation Source Hours Deg C Dalton mg/mL Control Control from 100% —— 22034 79 Hemmingway ARPRO Adhesive 1 Hydrolysate 1 100% 14 100 2050060 ARPRO Adhesive 2 Hydrolysate 2 100% 24 100 11600 42 (Low Temp. SoyFlour) Flour Adhesive 3 Hydrolysate 3 50:50 24 120 8120 106 Isolate andFlour Adhesive 4 Hydrolysate 4 25:75 24 120 9626 and 92 Isolate: 6626Flour Adhesive 5 Hydrolysate 5 100% 14 150 9420 108 (High Temp. FlourFlour)

Molecular weight and viscosity of hydrolysates decreased with increasesin time and temperature of hydrolysis reaction. Total amine level andwater solubility of hydrolysate increased with time and temperature ofreaction. Typical response curves are shown in FIGS. 2 and 3.Temperature had a more dominant effect than time on these parameters.Molecular weight, amine level and viscosity of hydrolyates have beensuccessfully correlated with time, temperature, and protein level(isolate versus flour) using statistically significant regressionmodels.

As seen in FIG. 2, molecular weight decreased rapidly as the hydrolysistemperature increased above 100° C. Further, molecular weightdistribution broadened. Regression analysis of the data showed favorableresults, in that an R² value of 0.98 was obtained between peak molecularweight and time and temperature of alkaline hydrolysis.

The solution viscosity of the hydrolysate decreased with an increase intime and temperature of hydrolysis due to breakdown of the proteinstructure resulting in lower molecular weight fractions. The R² valuefor the correlation of solution viscosity with time and temperature ofhydrolysis was 0.94.

FIG. 3 shows a typical response curve for total amine level as afunction of time and temperature of hydrolysis. Amine level increasedwith time and temperature of hydrolysis as the protein structure isunfolded, exposing buried amine groups, and also due to formation ofN-terminal amino acids resulting from the breakdown of polypeptidechains. Amine functionality has been successfully correlated tohydrolysis conditions with an R² value of 0.96.

EXAMPLE 3

Mixing Phenolic Resins with Protein Hydrolysates.

Hydrolysates derived from 100% soy flour and 100% soy isolate at 36%solids content were mixed with phenol formaldehyde resin (RPPB 16185from Georgia Pacific Resins, Inc.) and polymeric isocyanate resin (fromHuntsman Chemicals) separately to estimate the useful pot life of themixtures. If the viscosity exceeds 3000 cps, the resin binder cannot beused in oriented strand board production. A ratio of 1:1 for the proteinhydrolysate and synthetic resin (either phenol formaldehyde or polymericisocyanate) was used. Brookfield viscosity measurements showed that themixtures made up of soy flour hydrolysate and either the phenolformaldehyde resin or the polymeric isocyanate resin have a useful potlife of about 60 minutes.

Hydrolysates derived from 100% soy flour and 100% soy isolate wereevaluated as co-binders in combination with phenol formaldehyde andpolymeric isocyanate resin. The resultant protein hydrolysates weremixed as a co-resin with a phenolic resin binder to form a highlycross-linked thermo set matrix. Improved bonding performance wasobserved in soy protein derived adhesives due to strong chemicalreactions between the functional groups of the soy protein and phenolicresin and isocyanate binder.

EXAMPLE 4 Effects of Soy Hydrolysates on Bond Performance of Mixed ResinAdhesives

Experimental Procedure For Board Preparation and Testing

Property of Soy Hydrolysates and Soy/Resin Blend System.

Four soy hydrolysates were evaluated. The blend ratios of soyhydrolysate to phenolic resin were either 25:75 (based on solidscontent) or 50:50. Properties (i.e., pH, viscosity, and solids content)of soy hydrolysates before and after blending with phenolic resin weredetermined.

Flake Preparation and Blending.

All panels were made in the laboratory with mixed hardwood flakesobtained from a local flakeboard plant. To prepare each panel, flakeswere weighed out and placed in a rotating drum-type blender. The resinblend, in amounts equal to 4.5 percent of the dry weight of flakes, wasthen weighed and applied by air-atomizing nozzles. Average moisturecontent of the flakes after spraying was 11 percent.

Mat Forming and Hot Pressing.

After blending, the randomly oriented flakes were carefully felted intoa 17 by 17 inch box to form the mat. The mat was transferred immediatelyto a 20 by 20 inch single-opening hot press with the platen temperatureregulated at 370° F. Sufficient pressure (about 550 psi) was applied sothat platens closed to 1.2-inch thickness stops in approximately 45seconds. Press time was 4 minutes, 15 seconds after closure.

Sampling and Testing.

All boards were conditioned in a chamber controlled at 50 percentrelative humidity and 80° F. before testing; ending moisture contentaveraged 5.9 percent. After conditioning, each board was cut to yieldfour static-bending specimens and six specimens for tensile strengthperpendicular to the face (internal bond).

The mechanical tests were performed in accordance with ASTM standardsfor evaluating the properties of wood-based fiber and particle panelmaterials (D-1037-86). The properties tested included internal bondstrength (IB), modulus of rupture (MOR), modulus of elasticity (MOE),and thickness swell (TS).

Results and Discussions

Property of Soy Hydrolysates and Blended Soy/Resin System.

Average pH, viscosity, and solids content of hydrolysates and soy/resinblend system are summarized in Table 3 below. The pH range for soyhydrolysates was from 8.67 to 9.98. The average pH of the phenolicresins studied was 12.06. Thus, it was expected that the pH for thesoy/resin blend system would increase with an increase in phenolic resinin the blend system. Results suggest that the general rule of mixturecan be applied to the mixed system. The solids content of the soyhydrolysates ranged from 36.7 to 38.1 percent and the solids content ofthe phenolic resin was 51.4 percent. The solids content of thesoy/phenolic blends also increased as the phenolic resin contentincreased.

TABLE 3 Physical and Chemical Properties of Soy Hydrolysates Before andAfter Blending with Phenolic Resin. Before Mix After 25/75 Mix After50/50 Mix Visc., Solid Visc., Solid Visc., Solid Resin I.D. pH cps % pHcps % pH cps % 48177-8-01 8.67 3580 36.7 11.47 810 46.0 10.27 352.0 41.1(100 ISO) 48177-8-02 8.72 6130 38.1 11.45 780 46.4 10.24 2670 44.4 (100FLO) 48177-8-03 (50/50) 8.75 2490 36.9 11.52 545 458 10.81 1400 42.048177-8-04 9.98 1540 36.8 11.78 795 46.0 11.40 1870 41.9 (HT-1)

The general rule of mixture could also be applied to the viscosity ofthe mixed soy/resin systems. However, with the 50:50 soy isolate to soyflour blend, two of the hydrolysates (100 ISO and HT-1) yielded aviscosity equal to or higher than that of the unmixed soy hydrolysates.This indicates significant interactions between soy hydrolysates andphenolic resin, resulting in the increase of viscosity of the mixedresin system.

Strength Property.

Table 4 summarizes average MOE, MOR, and IB of flakeboards made from theresin adhesive systems. The 25:75 mixed system yielded slightly higherMOR than that of the 50:50 blended system. However, the 50:50 blendedsystem resulted in slightly higher MOE as compared to that of the 25:75blended resin system. On average, the phenolic resin bonded panelsconsistently yielded higher MOR and MOE than that of the mixed resinsystems.

TABLE 4 Strength Properties of Flakeboards. 25/75 Mix 50/50 Mix ResinI.D. IB MOR MOE IB MOR MOE 48177-8-01 100.7 3775 545750 42.6 3217 569250(100 ISO) 48177-8-02 92.0 3696 542600 61.4 3168 561950 (100 FLO)48177-8-03 (50/50) 91.4 4022 584150 48.5 3358 60000 48177-8-04 (HT-1)108.2 3585 552550 66.1 4134 623200 CONTROL 100% Phenol Formaldehyde112.0 4311 633350

Although the average IB of the phenolic resin bonded panel was slightlyhigher than that of 25:75 blended panels, the difference was ratherinsignificant (112 psi as compared to that of 98.1 psi). As the blendratio increased to 50:50, the IB decreased substantially.

Resin viscosity could have a profound affect on glue bond formation. Theoptimum resin viscosity for the manufacture of oriented strand board iscontrolled between 250 and 750 cps. The viscosity of the 25 soy:75phenol formaldehyde blends was at the upper range of optimum viscosityand that of 50 soy:50 phenol formaldehyde blends was significantlygreater than the upper viscosity range. The high viscosity of the resinblend would adversely affect resin distributions, and in turn decreasebond strength.

The solids content of soy hydrolysates (i.e., 36.7 to 38.1%) wassubstantially lower than that of phenol formaldehyde resin (i.e., 51%).The low solids content would add shipping costs and also have negativeeffects on the performance of soy hydrolysate because of the extra waterthat has to be handled in the processing of oriented strand board. Forinstance, water that enters the cellulosic fiber furnish as part of theliquid resin also makes up a portion of the final mat moisture contententering the hot press. Hence, at a 4.5 percent addition of thesoy/phenol formaldehyde mix resin solids, a maximum of 2.6 percent (for50 soy:50 phenol formaldehyde mix, based on resin solids content of 42%)is added to the furnish. Since the average moisture content of theflakes used was 7.5 to 8.5 percent, moisture from resin could raise thefinal moisture content to 10 or 11 percent. At this level, the matmoisture content approaches the allowable limit that the press couldtolerate, particularly when using a short hot press cycle.

EXAMPLE 5

Glue Bond Strength of Modified Soy Hydrolysates.

The effect of increased solids content of hydrolysate (See FIG. 1) wasevaluated. Four soy hydrolysates (48177-8 series) were modified, basedmainly on the results of Example 1 and prepared for evaluation. Sincethe 25 soy:75 phenol formaldehyde mix yielded satisfactory IB strengthand 50 soy:50 phenol formaldehyde produced inferior IB strength, a ratioof 35 soy to 65 phenol formaldehyde was chosen as the blend ratio inthis example. The methods used in Example 1 were followed generally.

Table 5 summarizes the properties of soy hydrolysates and soy/phenolformaldehyde mixed resin systems.

TABLE 5 Properties of Soy Hydrolysates and Mixed Soy/Phenol FormaldehydeSystems. Soy Hydrolysate Soy/PF Systems Visc., Solids Visc., % SampleI.D. pH cps % pH cps Solids 48018-35-02 8.84 10,400 42.2 11.08 1,69044.8 48177-08-06 8.88 1,400 37.0 10.72 1,450 43.3 48177-08-17 9.13 2,53033.1 11.00 620 40.3 48177-08-25 9.34 325 24.9 10.92 200 35.6

The viscosity decreased substantially in the mix of soy hydrolysate480180-35-02 (i.e., from 10,400 cps to 1,690 cps). The viscosity of theresin blend was satisfactory, but the high degree of viscosity build upin this short time may have affected the resin distribution. Theviscosity of the 48177-08-06 mix was slightly higher (1,450 cps) thanthat of the un-mixed hydrolysates (1,400 cps), suggesting significantinteractions between hydrolysates and phenol formaldehyde resin in themix. It was noted later that the interaction between the hydrolysatesand the phenol formaldehyde resin was high enough to cause difficulty inatomization of the resin mix system, and no panel was fabricated. Theviscosity of the 48177-08-17 blend was also decreased significantly from2,530 cps to 620 cps. As a result, this 48177-08-17 blend had theoptimum resin viscosity among the four resins tested. The very lowviscosity of the 48177-08-25 hydrolysates (i.e., 325 cps) yielded verylow viscosity of the resin blend system (200 cps), which was belowoptimum range. Low viscosity together with very low solids content werefound to cause high resin penetration and slower resin cure of thissystem.

The average IB for three resin systems are summarized as follows:

IB Resin I.D. Psi Standard Dev. 48018-35-02 56.3 6.9 48177-08-06 Badresin spray 48177-08-17 57.8 6.6 48177-08-25 55.2 6.9 Control Phenol91   10.3  Formaldehyde Resin

The differences in IB among the soy resins were not significant, withexception of the 48177-08-06 resin. The results seem to suggest that theprocess modification made on the soy hydrolyzation yielded no additionalimprovements in glue bond performance. Furthermore, the average IB's ofmixed resins were at least 39 percent lower than that of the controlphenol formaldehyde resin, indicating that optimum IB could not beobtained by 35 percent weight substitutions of phenol formaldehyde bysoy hydrolysates. Based on results from Examples 1, 2 and 5 it appearsthat the maximum level of substitution of phenol formaldehyde resin bysoy hydrolysate is between 25% and 30%.

EXAMPLE 6

Effects of Process Variables on Performance of Soy (48177-8-02)/PhenolFormaldehyde Resin Blend.

The effects of the process variables were evaluated using Soy(48177-8-02). The process variables evaluated were:

Soy/phenol formaldehyde ratios: 0/100, 25/75, 35/65, and 45/55

Resin content: 3.5, 4.5, and 5.5 percent

Hot press tempature: 340°, 370°, and 400° F.

Hot press time: 3.5, 4.5, and 5.5 minutes

An orthogonal experimental design method was used in the study. Table 5(6) summarizes IB strength of the resin systems.

The results show that hot press time is the most significant processvariable to affect IB strength, followed in order by hot presstemperature, soy/phenol formaldehyde ratio, and resin content. Thesignificant effect of hot press time and temperature indicate theimportance of resin cure rate. Therefore, in the hydrolysis process,molecular weight and amine level of soy hydrolysate were carefullycontrolled to balance optimum workable viscosity and favorable cure rateof the resin blend. However, no cure improvement was seen from varioussoy/phenol formaldehyde resin systems studied in this example. Thisobservation seems to relate to the fact that no hardener/catalyst wasused in this study to accelerate cure. It appears that the formaldehydecontent of the resin system is an important factor affecting cure rate.As the ratio of soy/phenol formaldehyde resin increases in the blend,the ratio of formaldehyde/phenol decreases. Decreases in theformaldehyde to phenolic ratio could eventually develop into a conditionof formaldehyde deficiency, adversely affecting resin cure rate andleading to weak bond with insufficient cross-linking.

TABLE 6 Summary Results of Internal Bond Strengths. Resin Hot-pressingPanel Performance Soy/PF Content Temp., Time, Density Aver. IB Std. Dev.IB No. Ratio % ° F. min PcF psi psi 0 0/100 4.5 370 4.5 48.0 63.3 16.3 125/75 3.5 340 3.5 45.9 14.0 14.1 2 25/75 4.5 370 4.5 48.8 48.7 18.9 325/75 5.5 400 5.5 49.0 93.5 11.0 4 35/65 3.5 340 5.5 47.8 54.3 6.8 535/65 4.5 400 3.5 49.0 36.8 12.0 6 35/65 5.5 340 4.5 48.2 48.3 10.9 745/55 3.5 400 4.5 48.0 40.5 11.9 8 45/55 4.5 340 5.5 48.6 41.7 13.4 945/55 5.5 370 3.5 46.9 12.6 11.7 AVER. K1 52.1 36.2 34.6 21.1 IB K2 46.442.4 38.5 45.8 K3 31.6 51.4 56.9 63.2 Range 20.5 15.2 22.3 42.0 *** 3rd4th 2nd 1st

FIG. 4 presents the relationship between IB and resin content, blendratio, hot press time and temperature. As expected, average IB increasedas resin content, hot press time, and press temperature increased.Furthermore, IB decreased as the blend ratio of soy/phenol formaldehydeincreased.

EXAMPLE 7

Addition of Paraformaldehyde.

Previous experiments suggested that the formaldehyde content in theresin system effects IB strength. In this example, the formaldehydecontent in the mixed resin systems was adjusted by the addition ofparaformaldehyde. Panels were made with two resin systems: (1) 25 soy:75phenol formaldehyde resin system without paraformaldehyde addition, and(2) 25 soy:75 phenol formaldehyde resin system with addition of 5percent paraformaldehyde (based on resin solids) prior to the resinapplication. Average strength properties were as follows:

Resin IB (psi) MOR (psi) MOE (psi) Without para 98.8 4382 565100 With 5%para 56.2 3466 521800

The addition of paraformaldehyde did not achieve the improvement instrength properties that was expected. The addition of paraformaldehydesignificantly increased the viscosity in a relatively short time period,indicating that paraformaldehyde addition accelerates resin cure.However, the rapid viscosity advancement suggests that the 5%paraformaldehyde addition may be more than is needed in the system. Nofurther optimization of paraformaldehyde was made in this study. Therewas some difficulty in mixing paraformaldehyde powder evenly andsmoothly into the resin system, suggesting that the regular 50%formaldehyde solution could have been a better choice for theapplication.

EXAMPLE 8

Addition of Phenol Formaldehyde Pre-Polymer with High Methylol Content.

High methylol content phenol formaldehyde pre-polymer was formulatedwith a molar ratio of formaldehyde:phenol:NaOH at 2:1:0.5 and reacted atvery low temperature for 36 hours. Three mixed resin systems werefabricated as follows: (1) Resin I (25 soy:75 pre-polymer mix), (2)Resin II (25 soy:37.5 pre-polymer:37.5 phenol formaldehyde resin mix),and Resin III (25 Soy:18.75 pre-polymer:56.25 phenol formaldehyde resinmix). Average IBs are summarized below:

Resin I.D. IB (psi) Resin I Blow (Delaminated) Resin II  76.0 Resin III119.0

Resin III seems to perform equal to or better than the soy/phenolformaldehyde resin system, indicating the potential for improvement ofstrength properties by the addition of highly reactive phenolformaldehyde pre-polymer into the resin system.

EXAMPLE 9

Strength Properties and Dimensional Stability of Soy/Phenol FormaldehydeBonded Panel Products.

The panel properties evaluated were based mainly on relatively smallsized panels (17 by 17 inch). The strength properties and dimensionalstability of larger sized panels (24 by 24 inch) were evaluated in thisstudy. The soy: phenol formaldehyde ratio was 30:70. The variablesconsidered in the experiment were:

Hot press temperature: 370° F. and 345° F.

Hot press time: 3.5 and 4.5 minutes

Resin content 3.5 and 4.5 percent

TABLE 7 Strength Properties and Dimensional Stability of FlakeboardsBonded with 30 Soy/70 Phenol Formaldehyde Resin System 370 F 340 F 340 FPress Press Press 370 F Temp. Temp. Temp. Press Temp. 4.5% 3.5% 4.5%Control Control. 3.5% RC PC RC PC 370 F 340 F IB MOR MOE LE TS WA 3.5min press 36.2 2209 618900 0.564 77.6 118.1 4.5 min press 49.0 2345579200 0.768 66.9 112.3 3.5 69.4 1973 578500 0.767 72.8 128.7 min press4.5 81.3 2715 737400 0.448 67.5 122.6 min press 3.5 min 11.36 2171526400 0.682 76.1 129.7 press 4.5 min 19.7 1950 624900 0.758 61.6 125.8press 3.5 min 26.9 2655 766800 0.822 65.8 109.2 press 4.5 min 43.9 2664670700 0.803 72.0 109.3 press 3.5% 40.2 1631 448700 0.816 55.0 124.4 RC3.5 min 4.5% 85.9 2714 693200 0.752 54.3 115.9 RC 4.5 min 3.5% RC 30.33314 727300 0.755 61.8 120.4 3.5 min 4.5% RC 65.5 4085 762100 0.623 50.2108.6 4.5 min LE = Linear Expansion WA = Water Absorption

In general, the results are in good agreement with the results fromprevious experiments. Some major observations are noted here: The phenolformaldehyde resin (used as control), had an IB value of 85.9 psi, whichis slightly lower than the average IB obtained in some of the previousexperiments. The low IB is due mainly to the slightly shorter hot presstime used in this example (4.5 min.) versus the hot press time used inprevious experiments (5.0 min.). In the soy/phenol formaldehyde resinsystem, for the same reason, the highest IB value is 81.3 psi, which isalso 10 to 15 percent lower than the previous IB value of 95 to 100 psi.In addition to shorter press time, the higher soy substitution of thesoy/phenol formaldehyde system employed in this study (30 soy:70 phenolformaldehyde ratio instead of 25 soy:75 phenol formaldehyde) is a factorcontributing to the lower IB. As hot press time and temperature aredecreased, strength properties decreased substantially. The overallthickness swell (ranging from 50.2 to 77.6 percent) was more than doublethe desirable thickness swell of 25 percent for most oriented strandboard panels. It is worth noting that even the phenol formaldehydecontrol had an unacceptable thickness swell of 50.2% to 61.8%. Comparedto the phenol formaldehyde control, the experimental 30 soy:70 phenolformaldehyde binder system is about 15% higher in thickness swell. It isnot clear why the phenol formaldehyde control system had such highthickness swell.

EXAMPLE 10

Effects of Isocyanate Addition on Glue Bond Strength.

Polymeric isocyanate (PMDI) is known to perform well as a binder in themanufacture of oriented strand board and agfiber board. In thisexperiment, the effects of isocyanate addition to soy/phenolformaldehyde resin systems related to strength properties anddimensional stability were evaluated. All panels were made with a hotpress temperature of 370° F. and a hot press time of 4.5 minutes. Theisocyanate addition expressed in term of percent resin content ratioswas:

2% PMDI:1% soy resin (30 soy:70 phenol formaldehyde blend)

1% PMDI:2% soy resin (30 soy:70 phenol formaldehyde blend)

1% PMDI:3% soy resin (30 soy:70 phenol formaldehyde blend)

Strength properties and dimensional stability of the panel products aresummarized as follows:

Resin I.D. IB (psi) MOR (psi) MOE (psi) LE, % TS, % WA, % 2% PMDI/1% Soy111.0 5566 754,000 0.438 18.7 93.3 1% PMDI/2% Soy 91.3 4353 677,0000.454 23.5 94.0 1% PMDI/3% Soy 93.3 5310 810,000 0.561 25.3 100.8 3%PMDI 115 5600 750000 0.441 19 94

The addition of polymeric isocyanate improved all properties of strengthand dimensional stability. The following points are worth noting: (1)thickness swell was in the desirable 25% range, (2) at equal rate oftotal resin applications (i.e., 3%), IB increased substantially (i.e.,91.3 psi to 111.0 psi) as the polymeric isocyanate content increased(i.e., from 1% to 2%), and (3) at equal polymeric isocyanate content(i.e., 1%), IB increased only slightly (from 91.3 psi to 93.3 psi) asthe soy resin content increased from 2% to 3%. For comparative purposes,typical literature values obtained for oriented strand board made with3% polymeric isocyanate are shown in the above table.

The most interesting result in the study is the performance of the resinsystem composed of 1% polymeric isocyanate/2% soy resin blend. Thestrength properties and dimensional stability of the panels made withthis resin system are equal to or better than the phenolic resin systemand approach the performance of polymeric isocyanate system.Furthermore, these preliminary results show that this resin system hasgreat potential as an alternative new resin system for wood compositesbecause of its attractive performance/cost profile.

In today's oriented strand board industry, application of polymericisocyanate resin is used at 2.5 to 3.5 percent resin content compared to3.5 to 4.5 percent used in phenol formaldehyde resin system. Assumingthe costs of isocyanate, phenol formaldehyde resin solid, and soy resinsystem respectively at 78, 40 and 30 cents per pound respectively, it isreadily seen that significant cost savings are possible with the use ofless expensive soy flour in a reduced polymeric isocyanate binderformulation.

Having described the invention in detail and by reference to embodimentsthereof, it will be apparent that modifications and variations arepossible without departing from the scope of the invention defined inthe appended claims. More specifically, although some aspects of thepresent invention are identified herein, it is contemplated that thepresent invention is not necessarily limited to these preferred aspectsof the invention.

What is claimed is:
 1. A cellulosic fiber composite comprising: acellulosic material; and a resin binder comprising vegetable proteinhydrolysates and a synthetic resin, wherein the synthetic resin isphenolic resin, isocyanate resin, or combinations thereof, and thecomposite contains an effective amount of resin binder so as to bindtogether the cellulosic materiel, wherein the amount of the resin binderis between about 2% and about 15% of the dry weight of the cellulosicmaterial.
 2. The composite as claimed in claim 1 wherein the amount ofthe resin binder is between about 4% and about 8% of the dry weight ofthe cellulosic material.
 3. The composite as claimed in claim 1 whereinthe amount of the resin binder is between about 4% and about 6% of thedry weight of the cellulosic material.
 4. The composite as claimed inclaim 1 wherein the amount of the resin binder is between about 4% andabout 5% of the dry weight of the cellulosic material.
 5. The compositeas claimed in claim 1 further comprising an average moisture contentbetween about 8% and about 35% by weight.
 6. The composite as claimed inclaim 1 wherein the vegetable protein is soy protein.
 7. The compositeas claimed in claim 6 wherein the soy protein is soy isolate.
 8. Thecomposite as claimed in claim 6 wherein the soy protein is soy flour. 9.The composite as claimed in claim 6 wherein the soy protein is a blendof soy isolate and soy flour.
 10. The composite as claimed in claim 9wherein the weight ratio of the blend of soy isolate to soy flour isabout 50:50.
 11. The composite as claimed in claim 1 wherein thesynthetic resin is phenolic resin.
 12. The composite as claimed in claim11 wherein the phenolic resin is phenol formaldehyde.
 13. The compositeas claimed in claim 11 wherein the resin binder has a weight ratio ofprotein hydrolysates to phenolic resin between about 10:90 and about90:10.
 14. The composite as claimed in claim 11 wherein the resin binderhas a weight ratio of protein hydrolysates to phenolic resin betweenabout 10:90 and about 75:25.
 15. The composite as claimed in claim 11wherein the resin binder has a weight ratio of protein hydrolysates tophenolic resin between about 25:75 and about 75:25.
 16. The composite asclaimed in claim 11 wherein the resin binder has a weight ratio ofprotein hydrolysate to phenolic resin between about 25:75 and about50:50.
 17. The composite as claimed in claim 1 wherein the syntheticresin further comprises paraformaldehyde.
 18. The composite as claimedin claim 17 wherein the weight ratio of the paraformaldehyde to thetotal of the protein hydrolysates and the synthetic resin is betweenabout 2:48 and about 15:35 based on 50% resin solids.
 19. The compositeas claimed in claim 1 wherein the synthetic resin further comprises highmethylol content phenol formaldehyde pre-polymer.
 20. The composite asclaimed in claim 19 wherein the molar ratio of formaldehyde to phenol toNaOH of the high methylol content phenol formaldehyde pre-polymer isabout 2:1:0.5.
 21. The composite as claimed in claim 19 wherein theweight ratio of the high methylol content phenol formaldehydepre-polymer to the total of the protein hydrolysates and the syntheticresin is between about 10:90 and about 90:10.
 22. The composite asclaimed in claim 19 wherein the weight ratio of the high methylolcontent phenol formaldehyde pre-polymer to the total of the proteinhydrolysates and the synthetic resin is between about 25:75 and about75:25.
 23. The composite as claimed in claim 1 wherein the compositefurther comprises a silicone, silane, or combination thereof.
 24. Thecomposite as claimed in claim 23 wherein the silicone, silane, orcombination thereof is applied as a coating to the composite.
 25. Thecomposite as claimed in claim 23 wherein the silicone, silane, orcombination thereof is added to the resin binder.
 26. The composite asclaimed in claim 23 wherein the amount of silicone, silane, orcombination thereof is between about 0.1% and about 1.0% based on thetotal amount of the cellulosic material.
 27. A finished cellulosic fibercomposite article prepared by the method comprising: a. mixing a proteinhydrolysate with a synthetic resin, wherein the synthetic resin isphenolic resin, isocyanate resin, or combinations thereof, to produce aresin binder; b. mixing an amount of resin binder with a cellulosicmaterial to form a cellulosic material/resin binder blend, wherein theamount of resin binder is between about 2% and about 15% of the dryweight of the cellulosic material; c. felting the cellulosicmaterial/resin binder blend to form a low moisture-content mat; and d.molding the low moisture-content mat at an elevated temperature andpressure, producing the finished cellulosic fiber composite article. 28.The article as claimed in claim 27 that further comprises a laminateoverlay.
 29. The composite as claimed in claim 1 wherein the syntheticresin is isocyanate resin.
 30. The composite as claimed in claim 29wherein the isocyanate resin is polymeric isocyanate.
 31. The compositeas claimed in claim 29 wherein the resin binder has a weight ratio ofprotein hydrolysates to isocyanate resin between about 10:90 and about90:10.
 32. The composite as claimed in claim 29 wherein the resin binderhas a weight ratio of protein hydrolysates to isocyanate resin betweenabout 10:90 and about 75:25.
 33. The composite as claimed in claim 29wherein the resin binder has a weight ratio of protein hydrolysates toisocyanate resin between about 25:75 and about 75:25.
 34. The compositeas claimed in claim 29 wherein the resin binder has a weight ratio ofprotein hydrolysates to isocyanate resin between about 25:75 and about50:50.
 35. The composite as claimed in claim 1 wherein the syntheticresin is a combination of phenolic resin and isocyanate resin.
 36. Thecomposite as claimed in claim 35 wherein the weight ratio of theisocyanate resin to the total of the protein hydrolysates and thephenolic resin is between about 25:75 and about 75:25.
 37. The compositeas claimed in claim 29 wherein the amount of isocyanate resin making upthe composite is about 1% to about 6% based on the total weight of thecellulosic material.
 38. The composite as claimed in claim 29 whereinthe amount of isocyanate resin making up the composite is about 1% toabout 3% based on the total weight of the cellulosic material.
 39. Thecomposite as claimed in claim 29 wherein the amount of isocyanate resinmaking up the composite is about 1% to about 2% based on the totalweight of the cellulosic material.